根据两点坐标和半径返回圆点坐标

GetCircleCenter(x1,y1,x2,y2,r){
        let c1 = (x2 * x2 - x1 * x1 + y2 * y2 - y1 * y1) / (2 * (x2 - x1));
        let c2 = (y2 - y1) / (x2 - x1);

        let A = c2 * c2 + 1;
        let B = (2 * x1 * c2 - 2 * c1 * c2 - 2 * y1);
        let C = x1 * x1 - 2 * x1 * c1 + c1 * c1 + y1 * y1 - r * r;
        //圆心坐标1
        let r_y = (-B + Math.sqrt(B * B - 4 * A * C)) / 2 / A;
        let r_x = c1 - c2 * r_y;
        //圆心坐标2
        // let r_y = (-B - Math.sqrt(B * B - 4 * A * C)) / 2 / A;
        // let r_x = c1 - c2 * r_y;


        return [r_x, r_y]
　},